Has anyone ever tried to retrofit a back up sensor to the rear bumper of a 99 expy.? I recall reading about an aftermarket set up that fit in/near the hitch area.

 

Not to the bumper, but I installed one on my 99 Expy, got the sensor from Costco, made brackets so it mounts above the license, and below the rear hatch. Hardly shows, and has worked flawlessly for several years. Its made by 'Smart Park', don't know if its still available or not. Electrically, all I did was tap into the backup light circuit.